Victor Schlegel (4 March 1843 – 22 November 1905) [1] was a German mathematician. He is remembered for promoting the geometric algebra of Hermann Grassmann and for a method of visualizing polytopes called Schlegel diagrams.
In the nineteenth century there were various expansions of the traditional field of geometry through the innovations of hyperbolic geometry, non-Euclidean geometry and algebraic geometry. Hermann Grassmann was one of the more advanced innovators with his anticipation of linear algebra and multilinear algebra that he called "Extension theory" (Ausdehnungslehre). As recounted by David E. Rowe in 2010:
In 1872 Schlegel published the first part of his System der Raumlehre which used Grassmann’s methods to develop plane geometry. Schlegel used his book to put forth Grassmann’s case, arguing that "Grassmann’s ideas had been neglected because he had not held a university chair." Continuing his criticism of academics, Schlegel expressed the reactionary view that
Schlegel’s attitude was that no basis for scientific method was shown in mathematics, and "neglect of foundations had led to the widely acknowledged lack of interest in mathematics in the schools."
The mathematician Felix Klein addressed Schlegel’s book in a review [2] criticizing him for neglect of cross ratio and failure to contextualize Grassmann in the flow of mathematical developments. Rowe indicates that Klein was most interested in developing his Erlangen program. In 1875 Schlegel countered with the second part of his System der Raumlehre, answering Klein in the preface. This part developed conic sections, harmonic ranges, projective geometry, and determinants.
Schlegel published a biography of Hermann Grassmann in 1878. Both parts of his textbook, and the biography, are now available at the Internet Archive; see External links section below.
At the Summer meeting of the American Mathematical Society on August 15, 1894, Schlegel presented an essay on the problem of finding the place which is at a minimum total distance from given points. [3]
In 1899 Schlegel became German national secretary for the international Quaternion Society and reported on it in Monatshefte für Mathematik. [4]
David Hilbert was a German mathematician and one of the most influential mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas including invariant theory, the calculus of variations, commutative algebra, algebraic number theory, the foundations of geometry, spectral theory of operators and its application to integral equations, mathematical physics, and the foundations of mathematics.
Josip Plemelj was a Slovene mathematician, whose main contributions were to the theory of analytic functions and the application of integral equations to potential theory. He was the first chancellor of the University of Ljubljana.
Felix Christian Klein was a German mathematician and mathematics educator, known for his work in group theory, complex analysis, non-Euclidean geometry, and the associations between geometry and group theory. His 1872 Erlangen program classified geometries by their basic symmetry groups and was an influential synthesis of much of the mathematics of the time.
Hermann Günther Grassmann was a German polymath known in his day as a linguist and now also as a mathematician. He was also a physicist, general scholar, and publisher. His mathematical work was little noted until he was in his sixties. His work preceded and exceeded the concept which is now known as a vector space. He introduced the Grassmannian, the space which parameterizes all k-dimensional linear subspaces of an n-dimensional vector space V. In linguistics he helped free language history and structure from each other.
Multilinear algebra is the study of functions with multiple vector-valued arguments, with the functions being linear maps with respect to each argument. It involves concepts such as matrices, tensors, multivectors, systems of linear equations, higher-dimensional spaces, determinants, inner and outer products, and dual spaces. It is a mathematical tool used in engineering, machine learning, physics, and mathematics.
Friedrich Wilhelm Karl Ernst Schröder was a German mathematician mainly known for his work on algebraic logic. He is a major figure in the history of mathematical logic, by virtue of summarizing and extending the work of George Boole, Augustus De Morgan, Hugh MacColl, and especially Charles Peirce. He is best known for his monumental Vorlesungen über die Algebra der Logik, in three volumes, which prepared the way for the emergence of mathematical logic as a separate discipline in the twentieth century by systematizing the various systems of formal logic of the day.
Christian Hugo Eduard Study was a German mathematician known for work on invariant theory of ternary forms (1889) and for the study of spherical trigonometry. He is also known for contributions to space geometry, hypercomplex numbers, and criticism of early physical chemistry.
Adolf Hurwitz was a German mathematician who worked on algebra, analysis, geometry and number theory.
Wilhelm Karl Joseph Killing was a German mathematician who made important contributions to the theories of Lie algebras, Lie groups, and non-Euclidean geometry.
Wilhelm Wirtinger was an Austrian mathematician, working in complex analysis, geometry, algebra, number theory, Lie groups, and knot theory.
Emil Weyr was an Austrian-Czech mathematician, known for his numerous publications on geometry.
Vector Analysis is a textbook by Edwin Bidwell Wilson, first published in 1901 and based on the lectures that Josiah Willard Gibbs had delivered on the subject at Yale University. The book did much to standardize the notation and vocabulary of three-dimensional linear algebra and vector calculus, as used by physicists and mathematicians. It was reprinted by Yale in 1913, 1916, 1922, 1925, 1929, 1931, and 1943. The work is now in the public domain. It was reprinted by Dover Publications in 1960.
The Quaternion Society was a scientific society, self-described as an "International Association for Promoting the Study of Quaternions and Allied Systems of Mathematics". At its peak it consisted of about 60 mathematicians spread throughout the academic world that were experimenting with quaternions and other hypercomplex number systems. The group's guiding light was Alexander Macfarlane who served as its secretary initially, and became president in 1909. The association published a Bibliography in 1904 and a Bulletin from 1900 to 1913.
Hermann Kinkelin was a Swiss mathematician and politician.
Margarethe Kahn was a German mathematician and Holocaust victim. She was among the first women to obtain a doctorate in Germany. Her doctoral work was on the topology of algebraic curves.
Ioannis "John" N. Hazzidakis was a Greek mathematician, physicist, author, and professor. He is one of the most important mathematicians of the modern Greek scientific era. His professor was world renowned Greek mathematician Vassilios Lakon. He also studied with famous German mathematicians Ernst Kummer, Leopold Kronecker, Karl Weierstrass. He systematically worked in the field of research and education. He wrote textbooks in the field of algebra, geometry, and calculus. Hazzidakis essentially adopted some elements of Lacon's Geometry. He introduced the Hazzidakis transform in differential geometry. The Hazzidakis formula for the Hazzidakis transform can be applied in proving Hilbert's theorem on negative curvature, stating that hyperbolic geometry does not have a model in 3-dimensional Euclidean space.
Carl Friedrich Geiser was a Swiss mathematician, specializing in algebraic geometry. He is known for the Geiser involution and Geiser's minimal surface.
Erhard Scholz is a German historian of mathematics with interests in the history of mathematics in the 19th and 20th centuries, historical perspective on the philosophy of mathematics and science, and Hermann Weyl's geometrical methods applied to gravitational theory.
Johann Jakob Burckhardt was a Swiss mathematician and crystallographer. He was an invited speaker at the International Congress of Mathematicians in 1936 in Oslo.
Günther Hans Frei is a Swiss mathematician and historian of mathematics.